This invention relates to sewing needles and the like and more particularly to a easy-threading needle of this type having a threading slot opening into the needle eye and a piercing point offset relatively to the needle axis and the eye toward the slotted side of the needle.
Ever since the invention of the sewing needle, the problem of threading the needle has existed. This is especially true in manufacturing facilities which perform stitching operations for the garment trades. Whenever a thread breaks, or a bobbin or spool runs out of thread, or a needle unthreads, the operator must go through the distressful threading operation of inserting the thread through the needle eye. The same problem is presented in tufting mills where a yarn must be threaded through a needle eye.
Although there has been a long felt need for a satisfactory solution to the threading problem, no such solution has been provided by the prior art. The prior art is inundated with various proposals and attempts directed toward a solution to this problem, but no known proposal has been found satisfactory, and at this time no known needle is being sold which overcomes the threading problem.
As exemplary of the prior art are the following United States patents which extend chronologically from 1963 through 1983 and illustrate the many attempts at a solution: U.S. Pat. Nos. 37,996 (Ambler); 497,926 (Piffard); 623,666 (Hodsdon et al); 653,886 (Roberts); 738,567 (Olsen); 1,235,751 (Yount); 1,878,915 (Trejo); 1,926,378 (Rattie); 2,221,419 (Antcliff); 2,561,502 (Diemer); 3,858,537 (Zocher) and 4,385,575 (Weber).
Inherent in the design of the known prior art easy threading or so called "self-threading" needles is that the thread tends to escape from the needle when back-tacking, i.e., sewing in reverse, and that they either have sharp projections or indentations which tend to snag on the fabric as it passes therethrough. Other problems involve chafing and tearing of the thread. In most of the prior art attempts the thread is directed into the needle eye through a thread slot. In the prior art attempts have been made to smooth or bevil the edges of the slot which actually has resulted in the strands of the fabric being guided into and snagged by the edges of the slot. In other of the prior art, thread and fabric protection has been provided by spring type members which normally close the slot thereby either making it impractical to construct or provide a notch type indentation which can not tolerate side pressures on the needle. In almost all of the known prior art the point of the needle is in line either along the axis of the needle, or offset but aligned with the axis of the eye as in Weber, and as the thread tends to ride up the wall of the yee on the needle down stroke, there is a tendency for the thread to slip out of the threading slot. Moreover, in the known patented art in which the thread slot enters directly into the needle eye, the slot is at or below the longitudinal center of the eye which has a tendency to result in jerking the thread out of the slot on the needle upstroke, especially when back-tacking.
Additionally, of the known needles that have been marketed in the past, satisfactory results would occur, if at all, only in certain types of sewing machines, such as certain of those having a hook rotatable about a horizontal axis. The known prior art needles that have been attempted to be used with the vertical axis hooks have not been satisfactory.